The practicality of TRIZ based conceptual solutions in solving tombstoning defects during SMD soldering

• Tombstoning occurs during surface-mount device soldering which leads to defects.
• Substance-Field modelling which is a TRIZ tool was used to develop solutions.
• New concepts for the solder paste, solder pad, and heating method were developed.
• Correlation to patents and industry standards were done for solution validation.
• Multidisciplinary engineering solutions lead to higher innovation level.

Tombstoning is a common defect that occurs due to the uneven heating of the solder paste during the soldering process of surface-mount devices (SMDs) on circuit boards. With electronics becoming smaller in size and lighter in weight, SMDs will continue to be more compact. This shall lead to even more tombstoning defects. In this research work, the Theory of Inventive Problem Solving (TRIZ) was used to develop conceptual design solutions that prevent tombstoning. It was to be determined if the concepts are practical for actual implementation. The specific TRIZ tools used were Substance-Field model, and 76 Standard Solutions. Focus was on the redesign of the solder paste, solder pad, and substitution of convection reflow process with induction heating process. These TRIZ based concepts were then compared to existing patents and industrial practices related to solving tombstoning. It is found that there are similarities between the concepts developed with TRIZ and the existing tombstoning solutions. These results indicate TRIZ derived concepts are practical and are of lesser risk to be implemented. Other existing tombstoning solutions could also be related back to the Standard Solutions of TRIZ. Furthermore, more tombstoning solutions could possibly be developed as there are other TRIZ tools available than the ones used in this research.

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